Melanoma in situ

A skin cancer doctor can diagnose melanoma by examining it closely with a dermoscope. It will usually have specific colours or structures that alert the doctor to the possibility of melanoma. Sometimes these clues to diagnosis are hard to see and the melanoma is suspected because of changed appearance in repeated dermoscopic photographs. When a melanoma is suspected, the doctor will surgically remove the suspicious spot (a procedure known as excision biopsy) so that a skin pathologist can examine the tissue and make a definitive diagnosis.

Treatment of melanoma

All melanomas must be surgically removed with a clear margin around the edge. In most cases, melanoma in situ must be removed with a clear margin of at least 5 mm of normal skin around its outer edge. The initial excision biopsy is rarely this wide, so usually once a melanoma in situ is detected, a further excision must be performed to ensure a clearance of at least 5 mm. If the melanoma is in a cosmetically sensitive area or if the function or movement of the area is likely to be affected, your skin cancer doctor may refer you to a plastic surgeon or the melanoma unit of a hospital for further treatment.

Learn more about excision and excision biopsy.

Follow-up: what happens next?

Further assessment

The risk of a melanoma in situ spreading to other parts of the body is extremely low. Your doctor will perform a full skin examination to check for additional melanomas or other skin cancers elsewhere on the body.

Specialist referral

In some circumstances, your doctor may refer you to another doctor or health service for further treatment or assessment. For example:

• A plastic surgeon can perform a wider excision of the melanoma to achieve a good cosmetic outcome or preserve function of the affected area
• A public hospital melanoma unit can offer a team approach where surgeons, dermatologists, skin pathologists and other specialties are involved in your care. Your doctor may refer you to a public hospital melanoma unit for further treatment, to get a second opinion on the initial skin pathologist’s report, or advice on future follow-up and treatment.

Further tests

For melanoma in situ, routine blood tests or imaging scans are not usually required, as the risk of spread is extremely low.

Recurrence or spread after appropriately treated melanoma in situ is extremely unlikely. People who have had melanoma have an increased lifelong risk of a new melanoma.

High risk patients

Some people have an especially high risk of developing further melanomas in future. These people include:

• People who have already had more than one melanoma.
• People with a strong family history of melanoma.

Mole mapping (total body photography) is sometimes recommended for people in these high risk groups.

Self-examination

Skin cancer self-examination is an important part of ongoing care. People can detect new or changing lesions between appointments; report these promptly.

People with a history of melanoma should ideally check their own skin every 1–2 months.

Skin checks for your family

Melanoma tends to run in families. If you have had a melanoma, your first-degree relatives (children, sisters, brothers and parents) have an above-average chance of developing melanoma. They should check their own skin regularly and consider yearly skin checks by a doctor or nurse.

Further information

For detailed information about melanoma diagnosis, treatment and follow-up, see the Melanoma Institute Australia guide to melanoma in situ (PDF)

References

Australian Institute of Health and Welfare. Skin cancer in Australia, 2016. 

Menzies S, Guitera P, Soyer P et al. What is the role of sequential digital dermoscopy imaging in melanoma diagnosis? Clinical practice guidelines for the diagnosis and management of melanoma, 2018. 

Sladden M, Nieweg O, Howle J et al. What are the recommended safety margins for radical excision of a primary melanoma (in situ)? Clinical practice guidelines for the diagnosis and management of melanoma, 2020. 

Sladden M, Nieweg O, Howle J et al. Updated evidence-based clinical practice guidelines for the diagnosis and management of melanoma: definitive excision margins for primary cutaneous melanoma. Medical Journal of Australia volume208 issue3, February 2018, pages 137-142, 2018.

Barbour A, Guminski A, Liu W et al. Ideal settings, duration and frequency of follow-up for patients with melanoma. Clinical practice guidelines for the diagnosis and management of melanoma, 2019.